Thanks for your time and expertise. Your comments and help about the previous hides are the kind of information we have been looking
for since we started the project. We now have some deer hides available to
experiment with. We have one in progress right now that we are trying to tan
with EZ-100. We took it out of the EZ-100 solution after 22 hours and it dried
very stiff and hard. We put it back in for another 18 hours and it still turned
hard. It was worked a lot while drying, but just wouldn't soften.
We took a couple of small pieces of the same hide (before it was put in the EX-100), tanned them in
Krome-tan and they came out great.
Our EZ-100 was mixed 1/2 oz per pound of damp hide (plus the salt)
and the Ph held right at 4 the whole time. Shall we go back in the EZ-100
for more time? What happens if the leather is over-tanned in EZ-100?
Relating to your earlier comments, how do you recommend "killing the lye"? We theorized that muratic
acid would be ideal since it would form sodium chloride (salt) in the
hide which seems like a good thing, since all the other solutions contain lots of salt
We will try the lime on the next one. We tried a sulfuric acid pickle on an
earlier deer hide and the results were not good (probably not the acid's fault)
I was less concerned about the hazards of hydrochloric(stomach acid)
than sulfuric(battery acid). However both are so dilute in the pickle
that I'm not too worried, except when the kids are preparing them.
Anyway, since the HCl is damaging to the hide, we will try something else.
I see some formic on the shelf. Maybe that's next.
We are having a lot of fun with this and learning some chemistry too.
Thanks again.
Dave and the kids
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that might be your problem?
-Brandon
No we didn't oil it yet. From past experience, the oil helps but
not as much as this hide needs. We decided to wait with the oil in case
we had do go back in the tanning bath again.
We have done some other hides with Lutan-F and chrome tan without oiling
and they were much softer than this one.
Over-tanning sacrifices stretch! And in Taxidermy this is an important quality. When the tanning agent (EZ-100) is dissolved in water with some small amount of salt, the ions are attracted to the protein fibers when your skins or capes are put into it. They attach themselves to the fibers normally within the initial 24 hour period. I recommend pulling the skins after 16-20 hours. Almost all skins are fully tanned after 16 hours. However, if you go beyond a 24 hour soaking, the ions, besides being linked to the protein fibers, now begin to look at adjacent tanning agent ions and they begin to "cross-link" together, creating a tighter leather. This is not desirable. Cross-linking also takes place in Lutan F (N) skins too! Both EZ-100 and Lutan F (N) are considered "fast" tannages.
As for oiling - oil aids in lubricating the skin simply by the charged fatty material it imparts to the fibers, as well as by chemically trapping water molecules in the the fibers too! A "good" tanned skin should have a 25% water content. Without the oil the skins fibers will collapse upon drying and become brittle, as well as shrink. A lot of shrinkage in Taxidermy work is NOT desirable! The oil also helps the finished skin or cape hold its "size" or original size! When you tan with EZ-100 or Lutan F (N), one of the advantages to the Taxidermist is that a 20" measured neck is still a 20" neck after the raw cape has been tanned. It doesnt shrink - the oil helps in holding its size. It also reduces shrinking as the cape dries, and likewise, less pinning is needed in the mounting process.
Muriatic is much too harsh an acid - and the Lime or Lye influence should be killed BEFORE pickling. Most tanners prefer using Ammonium Sulphate as a De-Limer. They mix 2.0 Ozs. per every 5 gallons of solution and soak the skins in it overnight (12 - 24 hours). Then rinse and pickle. Formic is a good pickling acid. But - keep your pickle covered since it also evaporative.
Good luck with your project - it should be very educational!
Best Regards,
Bruce Rittel